Research On The Down-hole Data Transmission And Adjust Method

With the development of world economy and the improvement of people’s livingstandard, the demand for petroleum is increasing. However, after decades of exploration ofbig petroleum wells all over the world, the water content in the well liquid is escalating yearby year, which inhibits the exploration. In addition, the new exploited oilfields are difficult toexploit due to the much deeper of the oil layer. Owing to characteristics of huge displacementand high lift, electrical submersible pump production (ESP) can be used in the oil wellswhich have low oil content and oil wells which are painstaking to exploit, therefore, it erns agreat popularity in this industry. Down-hole ESP multiple sensors monitor many work statusof the ESP, have huge effects on the operation, maintenance and fault identification of theESP.Taking the ESP down-hole multiple sensor as the research object, this paper exploitedtheir signal transmission channel characteristics. According to the three importantcharacteristics of waveform distortion, the corresponding signal conditioning method wasstudied. Basing on the exploited signal transmission method, the paper presentes the design ofthe down-hole ESP multiple sensor, and committed related experimental research work of thereliability, accuracy and other aspects.Basing on the study of a variety of domestic and overseas down-hole multiple sensorproducts as well as the research present situation, the paper analysis of the prototypeacquisition condition data of products made home and abroad, six operating conditionparameters of down-hole-environment pressure, pump inlet and outlet pressure, fluidtemperature, set temperature, the unit vibration and leakage current are determined. Analysisof signal transmission principles of the prototype equipment made home and abroad, confirmsthis paper researching on the down-hole ESP multiple sensor signal transmission andconditioning technology.Basing on the extremely low frequency electric power carrier, this paper studies thesignal transmission method of the down-hole ESP multiple sensor. The highest operatingfrequency of the extremely low frequency electric power wave carrier is determined by thecombination of electric power carrier communication channel characteristics, electric power carrier channel model and down-hole ESP multiple sensor signal transmission channelcharacteristics. Established the down-hole multiple sensor channel model and furtheranalyzed the down-hole ESP multiple sensor channel characteristics. Basing on the abovetheoretical analysis, this paper develops the down-hole ESP multiple sensor communicationline and the system transfer protocol.Among the channel characteristics of the down-hole ESP multiple sensors, theinterference characteristics, attenuation characteristics and delay characteristics cansignificantly affect the down-hole signal transmission. Aiming to combat the waveformdistortion problem caused by the three typical channel characteristics, this paper raised threekinds of methodology, signal filtering, signal integration and signal compensation, togradually process the star signal. In addition, the author developed the signal filter circuit,signal extraction and integration circuit, signal compensation circuit and program, anddebugged them with experiments.This paper performed the functional module division of the upper part and theunderground part, respectively designed function module circuits basing on the modularmethod, and then developed the corresponding software systems basing on embeddedoperating system μC/OS-Ⅱ. To address the mass storage of data problem, the storagecircuit was developed based on NandFlash storage and USB downloading. To resolve theproblem of remote communication, the remote communication module based on ModBusprotocol was developed in this paper. As for the difficult interaction of instrumenthuman-computer, development of secondary instrument upper part control interface based ontouch screen control methodology was raised. To minimize the down-hole sensor errorcaused by the temperature change, the author investigated the down-hole multi-sensortemperature compensation methods, and put forward specific improving measures.In the end, reliability of the system is verified through the component testing andscreening experiment, circuit board aging test, system continuum running test, andenvironmental experimentation. Through the calibration experiment, each parameter ofdown-hole sensor was calibrated. The capability of the down-hole ESP multiple sensor isverified through the experiment well test and production well test.